The disclosure relates to a wireless power transmitter, a wireless power receiver, and a method of wirelessly receiving power.
A wireless power transmission or a wireless energy transfer refers to a technology of wirelessly transferring electric energy to desired devices. In the 1800's, an electric motor or a transformer employing the principle of electromagnetic induction has been extensively used and then a method for transmitting electrical energy by irradiating electromagnetic waves, such as radio waves or lasers, has been suggested. Actually, electrical toothbrushes or electrical razors, which are frequently used in daily life, are charged based on the principle of electromagnetic induction. Until now, the long-distance transmission using the magnetic induction, the resonance and the short-wavelength radio frequency has been used as the wireless energy transfer scheme.
Until now, wireless energy transmission schemes include a remote telecommunication technology based on resonance or a short wave radio frequency in addition to electromagnetic induction.
Recently, among wireless power transmitting technologies, an energy transmitting scheme employing resonance has been widely used.
In a wireless power transmission system employing resonance, since an electrical signal generated between the wireless power transmitter and the wireless power receiver is wirelessly transferred through coils, a user may easily charge electronic appliances such as a portable device.
In addition, the wireless power transmitter may receive information of a state of the wireless power receiver to transmit power. If the wireless power receiver includes an additional communication channel or an additional communication unit in order to transmit data to the wireless power transmitter, the high cost is required. Accordingly, the wireless power receiver mainly employs a load modulation scheme to transmit the data. According to the load modulation scheme, the wireless power receiver recognizes the change of an input impedance of the wireless power transmitter by changing the load (impedance) of the wireless power receiver.
However, the conventional load modulation scheme is limited to a magnetic induction type wireless power transmission system.